Along with a recent increase in packing density and speed of semiconductor integrated circuits, the pattern line width of the integrated circuits is decreasing, and higher performance has been demanded for semiconductor manufacturing methods. Accordingly, as printing apparatuses (exposure apparatuses), ones using a KrF laser (248 nm), an ArF laser (193 nm), and an F2 laser (157 nm), are under development. In recent years, there are being developed exposure apparatuses using EUV (Extreme Ultra Violet) light, which is an exposure light having a wavelength far shorter (5 to 15 nm) than a conventional one. Electron beam (EB) exposure apparatuses using electron beams are also being developed increasingly. A wafer alignment apparatus employs an arrangement, as mainly disclosed in Japanese Patent No. 3,145,355, in which a Y stage 104 capable of moving in the Y-axis direction is arranged on a stage base 101, and an X stage 105 capable of moving in the X direction is arranged on the Y stage 104 (see FIG. 8).
Such an EUV or EB exposure apparatus is required to have a higher exposure accuracy, i.e., stage alignment precision. A stage serving as an alignment apparatus needs to be designed in the following manner.
(i) Since an allowance for a temperature change around a substrate is extremely limited, the substrate should be so arranged as to minimize heat transfer from a driving unit, or the like.
(ii) The substrate alignment precision should be increased, and moving members should be arranged in a noncontact manner so as to prevent contamination (dust) due to contact operation.
Under the current circumstances, heat generated in each driving unit becomes larger due to an increase in mass of a moving member and demands for higher acceleration. In a conventional alignment apparatus (FIG. 8) disclosed in Japanese Patent No. 3,145,355, the driving units (a stator 105a and movable element 105b) of the X stage 105 are arranged in the immediate vicinity of a substrate to be aligned and are susceptible to heat generated in these driving units. Also, the driving units of the X stage 105 are arranged on the Y stage 104, and the X stage 105 is guided by the Y stage 104 through hydrostatic bearings. For this reason, heat may be transmitted from the driving units (stators 104a as coils) on the Y stage 104 to the substrate support member 105c, without any heating element.
Conventionally, temperature-controlled air is blown around a substrate to control the temperature of a substrate support member, thereby suppressing influences of heat generation in a driving unit. However, an alignment apparatus for use in an EUV or EB exposure apparatus is arranged in a vacuum atmosphere free from heat transfer to a gas, and thus, it is impossible to perform temperature control by air conditioning. Accordingly, stage arrangements for suppressing to the utmost influences of heat generation in a driving unit have been demanded.